| In order to study the epidemic situation of the infectious bovine rhinotracheitis virus(IBRV)in scale cattle field in Henan Province,our research group has made a random sample survey about the cattle in 12 scale cattle farm in five areas in Henan Province(that included The east of Henan,West of Henan and South of Henan,Middle of Henan).Randomly selected cattle herds in different ages,different health conditions,a total of 400 blood samples,776 copies of nasal swabs and vaginal swabs samples were collected,and then they were extracted swab DNA and frozen preservation to be detected according to conventional methods of separation of serum.Fistly,the collected 400 serum samples were detected by Enzyme-linked immunosorbent assay(ELISA),and the results showed that 210.IBRV antibody serum accounting for 52.50%(210/400),the total positive rate and the field positive rate was 100%.The positive rate from low to high was Estern Hennan(20.00%),Middle Henan(36.75%),Northern Hennan(60.84%),Western Henan(84.62%)and Southern Henan(85.07%).Different ages showed different positive rate,and the positive rate in young cattle,calves,reserve 1 fetal,2 births,3 births,4 fetal bovine were18.18%,11.11%,59.00%,70.69%,66.67% and 60.71%,respectively.However,the average positive rate of IBRV in sick cattle was 57.14%,significantly higher than that of the healthy cattle with 51.52%.Results showed that widespread infection of IBRV in the cattle in Henan Province,slightly lower than that in the suevey in 2010,but still was in a higher level.With regard to the five areas,results showed that reduction in the positie rate of IBRV in Este of Henan and Middle of Henan,increase with various degrees about the West of Henan,South of Henan and North of Henan.Finally,we found that many clinical symptoms of IBRV infection and cows have close relationship,which is suffering from mastitis and reproductive disorders in cattle and the average positive rate higher.And 776 swab samples in the collected 440 cows were detected by using Real-Time PCR,and 68 cattles showed a positive rate with a total positive rate15.45%(68/440)and positive rate in the field was 100%.Among these,the highest positive rate in the field was 68.00% and the lowest one was 6.67%.The positive ratefrom low to high was Estern Hennan(10.00%),Middle Henan(10.78%),Northern Hennan(12.04%),Western Henan(20.00%)and Southern Henan(35.82%).Different ages showed different positive rate,and the positive rate in young cattle,calves,reserve 1 fetal,2 births,3 births,4 fetal bovine were 3.57%,6.67%,23.53%,26.22%,14.55% and 28.57%,respectively.However,the average positive rate of IBRV in sick cattle was 28.13%,significantly higher than that of the healthy cattle with 13.23%.The positive rate of swab was lower compared to that in the serum epidemiological survey,but the two results were the same,which could reveal the infectious condition in different areas effectively.Among these,the positive rate in West of Henan and South of Henan were higher than that in East of Henan,Middle of Henan and North of Henan.The positive detection rate of swab samples showed a rising trend withe the increasing age.Among swab positive rate in different health status of cattle,the positive rate in mastitis in cattle was the highest.The experiment was conducted by the combination of serological and etiological investigation,and the IBRV positive rate of cattle swab was tested by the use of Real-Time PCR method at first time.Detailed analysis of serum antibody positive rate and swab based on different areas,ages and health condition showed that a close relationship among age,the body of the animal health,the distribution of cattle,feeding management and sanitation etc.This study revealed there were a prevalence of infection of IBRV of scale cattle farm in Henan in the selected five regions,which could provide a reference of the prevention and control of IBRV in large-scale cattle farm. |
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